This invention relates to a sample container system which is preferably compatible with the industry standard 96-well microtiter plate system. Such a plate system is disclosed in U.S. Pat. No. 3,349,937 to Duff et al. The present invention particularly relates to a test tube cassette system which is preferably constructed on an 8.times.12-0.354 inch on center geometry so as to allow it to interface with the standard 96-well microtiter plate. Such construction allows known pipeting equipment, such as disclosed in U.S. Pat. No. 4,446,104 to Hammerling et al., to be used to transfer multiple samples from the test tube cassette system into 96-well plates for further analysis. While this particular field of the invention is preferred, it will be recognized that certain aspects of the present invention are applicable outside the specific field discussed hereinabove.
A variety of test tube rack constructions are known. It is also known to provide a disposable rack of 96 micro test tubes for use in conjunction with microtitration plates and the pipeting equipment used therewith. One example of such a system is the Bio-Rad 1 ml. Titertube micro test tubes which are available in racks of 96 micro test tubes which match the spacing of multi-channel pipets, micro titration plates and MTT-rack pipet tips. The system also provides for polyethylene plugs to be provided in strips of eight plugs for sealing the micro test tubes. These strips of eight plugs may be cut apart to isolate the tubes.
Other known sample storage systems include the Skatron 1.0 and the 1.4 ml Microwell tubes. These individual round tubes are available in flexible strips of 12 attached at the top by means of a breakaway element. Stoppers are not available. Another sample storage system is the Nunc Microwell Module system. This system consists of a plastic frame and individual modules. Modules are available either strips of 2.times.8 round wells or 1.times.8 round wells. Each well has a volume of 0.3 or 0.4 ml.
The aforementioned known sample storage systems suffer from a number of disadvantages. For instance, the small volumetric capacity of the individual tubes of known sample storage systems precludes the collection of samples large enough to perform many different types of tests on the same sample and to perform repeated analysis on the same sample. The small compartment also precludes the collection of large samples required for chemical or enzymatic reactions for analytical purposes which require large volumes because the solutes or biological materials including receptors and hormones are present in low concentration. Further, in the case of identification of components of chromatographic separation, the small sample size limits the number of different types of tests on the same sample and the ability to perform repeated analysis on the same sample.
Further, known systems typically utilize tubes which are round. These round tubes are inefficient in terms of volumetric capacity. Moreover, the curved walls of these round test tubes adversely effects the optical characteristics of the tubes for at least two reasons. First, the curved walls provides less uniform light transmission than is possible with planar side walls. Second, the variable light path available in the conventional 96-well plate is less desirable than the fixed light path available when planar side walls are employed.